A note on the petrology of some lava types from East New Guinea |
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| Authors: | W R Morgan |
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| Institution: | Geology Department , University College , Townsville, Queensland |
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| Abstract: | Quaternary and upper Tertiary lavas from the volcanic islands along the north coast of east New Guinea consist of pyroxene andesites, andesitic basalts, and basalts; many contain accessory olivine. The lavas of Mts Lamington, Yelia, and Victory, in southeast Papua and New Guinea, are rather more acid hornblende and lamprobolite andesites. Peralkaline obsidian and rhyolite occur at Fergusson and Dobu Islands, east of the Papuan mainland. Chemical analyses show that most of the lavas are of calc‐alkaline type, although some from Karkar and Long Islands appear to have tholeiitic tendencies. |
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